HELP-PCI: A Fleeting Advantage of Early Heparin in ST-Elevation Myocardial Infarction?

In ST-elevation myocardial infarction (STEMI), immediate reperfusion through primary percutaneous coronary intervention (pPCI) remains the treatment of choice. However, the interval between the first medical contact (FMC) and access to the cath lab offers an opportunity for pharmacological interventions that can modulate thrombotic burden and promote early coronary patency.

Unfractionated heparin (UFH) is a fast-acting, widely available anticoagulant recommended by current guidelines. Nevertheless, the optimal timing of its administration—whether at the FMC or immediately before angioplasty—remains uncertain. The HELP-PCI study, by Chen et al., evaluated whether administering UFH (100 U/kg) earlier at the FMC could improve spontaneous angiographic reperfusion before the procedure without increasing bleeding risk.

A total of 999 patients with STEMI within 12 hours of symptom onset were enrolled across 36 centers in China. Participants were randomized 1:1 to receive UFH (100 U/kg) at the FMC or in the cath lab, just before angiography.

All patients received dual antiplatelet therapy (DAPT) loading at FMC, and procedures were performed according to current standard practice, predominantly via radial access (95.7%).

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The primary endpoint was the proportion of patients with TIMI 3 flow in the culprit artery before PCI. Secondary endpoints included complete reperfusion after angioplasty and the incidence of major adverse cardiovascular events (MACE) at 12 months. Safety was assessed through the incidence of BARC ≥2 bleeding.

The mean time from FMC to UFH administration was significantly shorter in the pretreatment group (35 min vs. 71 min). TIMI 3 flow prior to PCI was achieved more frequently in the early heparin group (23.6% vs. 17.6%; OR 1.44; 95% CI 1.06–1.97; p=0.02). Moreover, there was a time-dependent relationship between the UFH–guidewire interval and the likelihood of achieving initial TIMI 3 flow (adjusted OR 1.05 per 5-minute increment; 95% CI 1.02–1.09; p=0.003), suggesting an effect related to the duration of anticoagulant exposure.

Despite this angiographic improvement, complete post-PCI reperfusion—defined as the combination of TIMI 3 flow, optimal myocardial perfusion, and ST-segment resolution ≥70%—was similar between both groups (59.0% vs. 58.5%; p=0.97). Likewise, no significant differences were observed in major clinical events at 12 months (5.5% vs. 6.7%; HR 0.82; 95% CI 0.50–1.35; p=0.44).

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The safety profile was favorable: BARC ≥2 bleeding events were infrequent and comparable at both 30 days (0.4% vs. 1.2%) and 12 months (1.4% vs. 2.0%; p=ns).

Conclusions

The HELP-PCI study demonstrates that administering unfractionated heparin at the first medical contact significantly improves spontaneous patency of the infarct-related artery before PCI, without increasing bleeding risk. This effect may facilitate earlier reperfusion, although it did not translate into sustained long-term clinical benefits.

The strategy represents a simple, safe, and potentially valuable approach in settings where delays exist between diagnosis and mechanical reperfusion.

Original Title: Heparin administration at first medical contact vs immediately before primary percutaneous coronary intervention: the HELP-PCI trial.

Reference: Chen J, Xu C, Qiu L, Li B, Yao W, Wu H, Hu L, Xu G, Zhu D, Li Z, Wu X, Xiao C, Liu B, Shen X, Deng Z, Zhuo C, Su H, Yang K, Zhang Y, Zhang M, Li C, Lv X, Hong L, Guo F, Wu X, Xu H, Li M, He L, Wu W, Lei Y, Li D, Li H, Chen S, Bao H, Xiong X, Liu B, Yang G, Chen J, Lan X, Zheng Q, Yang G, Zhang M, Yang J, Jiang H. Heparin administration at first medical contact vs immediately before primary percutaneous coronary intervention: the HELP-PCI trial. Eur Heart J. 2025 Oct 14;46(39):3888-3901. doi: 10.1093/eurheartj/ehaf481. PMID: 40748607; PMCID: PMC12517749.